UNIVERSITY PARK, Pa. — Sleep and exercise are vital to the wellbeing of new parents, but these essentials affect new moms differently than new dads, according to researchers.

In a study looking at the daily lives of new parents, a team led by Penn State researchers found that in general, getting more physical activity and more sleep from day to day was linked with more personal well-being, a better couple relationship and more closeness with their baby.

However, fathers who slept more on average than other fathers reported lower overall well-being and less closeness with their partner and child. In contrast, mothers who slept more on average than other mothers reported greater well-being.

Additionally, the researchers found that on days when fathers exercised more than usual, there was a lower likelihood of an argument between the couple. But, on days when mothers exercised more than usual, there was a higher chance of an argument.

Mark Feinberg, research professor in the Edna Bennett Pierce Prevention Research Center at Penn State, who led the study, said these differences may be due to mothers often being seen as the primary caretaker.

“Fathers may resist or feel resentful when mothers spend more time than usual on their own needs such as exercise, leaving fathers to pick up more responsibility for child care — leading to arguments,” Feinberg said. “But, it’s also possible that the extra time spent with the child is stressful for fathers, leading fathers to be more irritable on such days and leading to more arguments with the partner.”

The findings — published in the Monographs of the Society for Research In Child Development — were part of a study that examined how factors like exercise, sleep and different daily stressors affected the day-to-day lives and family relationships of new parents.

Feinberg said that while early parenthood is stressful for parents both as individuals and as a couple, it is also a vital period of rapid development for the newborn child, making it especially important to understand and support parents’ well-being during this time.

“In general, new parents report higher levels of stress, depression and couple conflict, as well as less sleep, companionship and romance with their partner,” Feinberg said. “Ironically, it’s also the period when children are most vulnerable, when their brains and regulatory systems are rapidly developing to set the stage for their functioning for the rest of their lives, and when they are most dependent on parents for consistent affection and support.”

According to Feinberg, the current study is one of the first to explore these stress and resilience factors among new parents on a daily level.

He said that looking at how changes in one stressful or replenishing factor are linked to changes in parents’ well-being and relationships from day to day — instead of annually, for example — can give researchers a better understanding on how to help parents achieve better functioning and well-being on more days.

“In past research, we might find that on average, one father sleeps more, is less depressed, and more affectionate with his child than another father,” Feinberg said. “But that doesn't tell us if enhancing sleep for that father would affect his level of depression or parenting warmth.”

For the study, the researchers used data from 143 mothers and 140 fathers collected ten months after their child’s birth. The researchers interviewed the mothers and fathers separately by phone every night for eight days to gather data about the previous 24 hours.

They gathered data about time spent sleeping, at work, doing chores and physical activity. They also asked the participants about stress, well-being, and their relationships with their spouse and child.

Feinberg said the results may be used to help parents find and reinforce their strengths and have more good days than bad.

“Some parents are happier or sleep better overall than others, but most parents experience some difficult days and some good days,” Feinberg said. “Most parents already have a good place to start from at least on some days, so it’s a matter of figuring out what works on those days and then doing more of that. This would be an easier and maybe more effective approach than thinking that we have to help someone completely change their routines and emotional patterns.”

Additionally, Feinberg said parents may be able to explore their own day-to-day dynamics by using mobile apps on a smartphone.

“Studying daily fluctuation is a very rich way to understand the complex unfolding of individual and family life,” Feinberg said. “There are many apps and devices that are available for recording daily experiences such as sleep and physical activity. With a little bit more added functionality — being able to look at patterns across different experiences, and even across family members — these tools could provide even more benefit.”

David Almeida, professor of human development and family studies at Penn State; Damon E. Jones, assistant research professor in the Edna Bennett Pierce Prevention Research Center; Brandon T. McDaniel, assistant professor at Illinois State University; and Siwei Liu, assistant professor at the University of California, Davis, also participated in this work.

The Eunice Kennedy Shriver National Institute of Child Health and Human Development helped support this research.